1. Field of the Invention
The present invention relates to an electrodynamic transducer, and more particularly to an electrodynamic transducer for playback from phonograph records.
2. Description of the Prior Art
In a known electrodynamic sound pick-up, two coils perpendicular to each other in a magnetic field are supported by a cantilever arm held fixed at one end to cause the center of oscillation to be located at that end. The coils are spaced a certain distance from the fixed end and are connected to the cantilever arm by an insulating supporting member. Such a structure allows a relatively large amplitude of movement for the coils so that a relatively large amount of magnetic flux can be intersected by the coil windings. As a result, a high signal voltage, or a high transducer output voltage, is obtained. However, the inertial moment of oscillation of such a structure is high because the path of movement of the coils requires a large radius.
There are existing electrodynamic transducers of another type in which two triangularly shaped coils are arranged on both sides of and parallel to a cantilever arm capable of oscillating in any direction. The structure requires a wide, and thus disadvantageous, air gap, since the effective coil sections located in the gap are arranged one behind the other.